In the past, Japanese Patent Publication JP 2000-246883 has disclosed a printer that prints a title of characters on an optical disc (recording medium) such as a CD-R.
Generally, commodity information including, for example, a character string “CD-R” has been printed beforehand by its manufacturer on a specified area of an optical disc such as a CD-R. Preferably, a user prints a title of characters on the optical disc outside a print area for the commodity information so that the title is parallel to and alongside the character string indicative of the commodity information.
The above mentioned prior art printer has the function of printing a title of characters on an optical disc such as CD-R so as to be parallel to and alongside the character string indicative of the commodity information printed beforehand on the optical disc.
To this end, the prior art printer comprises a tray sliding mechanism that moves into and out of the printer body a tray on which the optical disc is set horizontally, a printing mechanism that moves a printing head in the direction perpendicular to the moving direction of the tray to thereby print on the optical disc set on the tray received within the printer body, and a camera that picks up an image on a surface of the optical disc.
The prior art printer senses an angular position of the optical disc on the tray based upon the image of the optical disc picked up by the camera. When it is sensed that the optical disc is rotated through a specified angle from a reference angular position on the tray, the character string of the title to be printed is rotated through the specified angle and then printed on the optical disc in order to print on the disc the character string of the title parallel to that of the commodity information.
In this printer, when the extending direction of the character string of the commodity information printed beforehand on the optical disc set on the tray, perpendicular or parallel to the moving direction of the tray, is defined as a reference angular position.
In this printer, the angular position of the optical disc on the tray is sensed by obtaining an angle (quantity of rotation) of the character string indicative of the commodity information to the reference direction based upon the image data on the optical disc set on the tray. The character string of the title is rotated through the obtained angle, and then printed based upon data on the rotated character string so that the character string of the title is parallel to that of the commodity information.
Therefore, according to the prior art printer, even when the user sets the optical disc on the tray in any angular position and not in a predetermined reference angular position, the character string of the title is printed in the same direction as and alongside the character string indicative of the commodity information, which is convenient for the user.
In the prior art printer, however, a camera is required that picks up an image of the surface of the optical disc to sense the angular position of the optical disc on the tray. A quantity of rotation of the optical disc needs to be sensed based upon the image data obtained from the camera. In addition, rotation of the character string of the title is required based upon the sensed quantity of rotation. This renders the composition of the printer complicated and increases the cost.